Combined gate and riser



9 M. BEAN 2,291,783

COMBINED GATE Am) RISER Filed Aug. 1, 1940 4 Sheets-Sheet 2 INVENTORName/.5 BfA/V Aug. 4, 194 2. 'M. BEAN COMBINED GATE AND RISER iled Aug.'1 1940 4 sheets-she t :s

INVENTOR Mame/5 65AM. A 5 rzanf ATTORN Y Patented Aug. 194 2 comimrnears sun-mean Morris Bean, Ieilow Sprints. Ohio V Application August 1,1940, Serial No. 349,033

This invention relates to the art of metal casting and more particularlyto novel structures combining a pouring gate and a riser in connectionwith metal casting molds.

In making a metal casting by filling a mold withliquid metal there arecertain principles which are used in order that the finished casting maybe made of sound, clean metal.

9Claims. 22-134) Accordingly, it is an object of the invention toefi'ect important economies by reduction'of the amount of metal requiredfor pouring each casting, thus reducing melting costs and also theproportion of, metal which must be cut from the casting in the form ofgates and'risers and subjected to remelting, with the usualconcomitantlosses and deteriorations.

In order that the metal maybesound ,it is necessary that the familiarchange in' volume with change of state be compensated for. In almost allof the commercial alloys there is a decrease in volume accompanying thechange from the liquid to the solid state. In order to prevent thisphenomenon from leaving unsound and spongy sections in the casting it isnecessary that a reservoir of liquid metal be available as the castingfreezes, and that this be connected to the casting in such a way that,immediately after the mold cavity is full, the casting freezesprogressively toward this reservoir, or riser. The riser, of course,must be the last to freeze ofl. Liquid metal, when it is available, willflow into the intercrystalline cavities of contiguous metal which isfreezing off and feed it, thus I preventing any'difiiculty fromshrinks."

This principle may perhaps be made more clear by presenting it asfollows: If an irregular. mold cavity is filled with metal which shrinkson freezing, and the metal is allowed to freeze, the heaviest sectionsof metal, which are the last to solidify, will be full of characteristicshrinkage cavities. In the method with which I am here concerned a soundcasting is assured by making this shrinkage occur outside the castingproper, that is, by putting it in a riser. This riser must be attacheddirectly to the casting or by a heavy connector. If too lighta connectoris used it will freeze off before thecasting proper, and the riser willnot have an opportunity to perform its function. To the same end theriser pref.-

erablyshould be located and designed so that This metal,

preferably, should not be allowed to run through the hottest metal is inthe riser.

Another object of the invention is to produce uniformly sound castingsof high quality. Another object-of theinventionis to simplify thepouring and gating of molds for casting.

Another object of the invention is to provide a pouring gate which willeffectively skim the metal cast into the mold.

Another object of my invention is to so desig a gating arrangement thatthe metal occupying the downpour gate when themold is full will functionintegrally with that in the riser to feed the casting as it freezes.

Another object of the invention is to effect important economies byreduction of the amount of metal required for pouring each casting and Ithus reducing melting costs and scrap losses.

Other objects of the invention will ap ar from the followingspecification and the accompanyingdrawings.

In the preferred embodiment of my invention, I provide a combined gateand riser unit which maybe assembled and used as a unit and-applied tovarious molds.

.A gating arrangement which has the basic essentials for making soundclean castings has (1) a down-pour gate; (2) passage from the gate intothe mold cavity having a choke or skim bob, this passage designed,wherever possible, to

allow the metal to run into the bottom of the mold andrise therein, thuspreventing turbulence with accompanying trapped air and *formation ofoxide films; (3) a riser connected directly to the mold cavity through awide passage; and .(4) the riser and the passage so related to the massof. metal in the riser as toavoid freezing of the metal in the riser andin its connection to the casting until after the freezing of the castingitself.

In the accompanying drawings I have shown a preferred embodiment of myinvention, and in the following specification I shall suggest variousmodifications thereof. It is to be understood that these are notintended to be either exhaustive or limitingmf the invention, but on thecontrary' are chosen for the purpose of illustrating the invention, inorder that others skilled in the art may so fully understand theinventhrough the combined gate and riser and portion of the connectedmold;

Fig. 2 is a top plan view of the unit of Fig. 1; Fig. 3 is a verticalsection taken on line 33 of Fig. 2;

Fig. 4 is a sectional view similar to that of Fig. 1, butshowing amodified unit embodying the invention;

Figs. 5 and 6 are diagrammatic sectional views showing'in comparison themetal necessary outside of the mold in the conventional practice andaccording to my invention respectively;

Figs. 7 and 8 are views similar to Figs. 1 an 3 respectively, butshowing another modified form of the invention; v

Fig. 9 is a fragmentary view in horizontal section showing a twin moldembodying the invention; and

Fig. 10 is a view similar to Fig. 9, showing a multiple mold embodyingmy invention.

Referring first to Figs. 1 to 3 inclusive, I have shown at H) afragmentary portion of a plaster mold designed, for example, for castingaluminuin 0r bronze. At the end of this is an opening ll through whichthe molten metal is fed into the mold cavity l2. A cavity of the sizeshown will ordinarily be provided witha core l0. Connecting with theopening ii, I have formed the .end of the mold with a recess l3, whichin this case constitutes a part of the combined gate and riser when themold isassembled with the gate and riser unit as more fully describedbelow.

The gate and riser unit shown in pouring position in these figuresconsists of two separate channel portions l4 and I5, forming the outerportion of the riser and gate respectively and the former adapted toregister with and form a continuation of the recess I3. The portions i4may collect on thesurface of the molten metal and fiow with it into thepouring gate.

In the use of this device the metal is poured into the funnel at theupper end of the pouring gate channel member l5 through which it fiowsdown behind the separator l9 and through the opening 20 into the riserchannel 13 and thence into the opening 1 l and finally into the moldcavity I2. As the metal rises in the mold cavity, it rises, of course,correspondingly in the riser channel l3l4. When the mold is finallyfilled and the pouring stopped the level of the metal will be at thesame height on both sides of the separator l9 and advantageously closeto the top of the channels I4 and I5 so as to provide a head" orhydraulic pressure on the metal within the cavity l2.

As the metal within the mold cavity l2 chills and freezes, itscontracts, as already described above. So long as the metal in the riserchannel l3l4 and in the opening ll remains molten and connected with thecasting by a channel of molten metal, such metal will be available tofeed the inter-crystalline cavities of the metal as it freezes ofi, andthus spongy portions and other imperfections in the casting can beavoided.

. Due to the relatively large opening shown at H, and due to'the factthat this opening II is surroundedby molten metal, both on the insideand the outside of the mold, the metal in the opening ll does not freezeuntil after the castand I5 are made of a refractory insulating ma-.terial. In most cases I find it advantageous to make these of a porousfully calcined plaster or other material with relatively high insulatingvalue.

These channel parts [4 and I5 are held together in assembled relationand given additional strength to resist the weight and impact of thepoured metal, and protect them against clamping forces and shocks towhichthey may be accidentally subjected, by the sheet metal sectionslB-Il clamped together to form a casting for the combined gate and riserby means of the U- clamps I8, which are made of resilient steel anddriven over the projecting edges of the casin members Iii-41.

Clamped between the members l4l5 and in this case extending betweenthesheet metal sec 'tions lS-i'l is a separator IQ of a refractory sheetmaterial, preferably of an insulatingnature so that it does not conductheat away from the mass of metal in the gate and riser unit; I havefound it advantageous to use for this separator IS a sheet of asbestospaper. Near the bottom of this separator I9 is a relatively smallopening 20 through which the metal must pass from the pouring gate intothe riser and before passing into the mold; thus, this partition l9 actsas a skimmer or choke to keep the metal clean and to hold back any drossor oxides, etc., which ing; and likewise, due to the insulation of thecolumn of metal in the combination pouring gate and riser unit, metal inthe riser does not freeze until after the casting and the connector II.

I should like particularly to emphasize that with my arrangement themetal finally occupying theriser is the hottest present. This is truefor two reasons: (1) this riser is finally filled up with the last metalto be poured from the ladle, and (2) the metal in the riser has beencooled ofi by flowing through any portion of the mold. Also, with 'myarrangement it is possible to first introduce the metal into the moldthrough a low opening therein, and let it rise gently in the moldcavity, thus preventing the entrapping of air and the formation of oxidefilms which are the results of turbulence.

I find that my castings are extraordinarily clean and free of drossbecause the metal is so effectively skimmed by flowing through the slotsI have provided. 1

It is important in obtaining these results that the riser and the gateare, as shown in the drawings, in close heat-exchange relation andtogether are insulated from the outside atmosphere.

metal poured into the pouring gate is added to the heat of the metal inthe riser itself, thereby serving to delay the final freezing of themetal in the riser; and, once the pouring is stopped, the

two channels continue to act together as a single riser and in this waythe metal left in the pouring gate replaces metal which otherwise wouldhave to'be accumulated in the riser and the total amount of metal pouredfor each casting is thus substantially reduced with correspondingreductions in melting costs, in the capacity of melting and pouringequipment required, in the number of castings which can be made in onepouring and in the losses and deteriorations which occur upon reclaimingand remelting of the gates and risers. Moreover, the recovery of thegatesand risers and their removal from the final casting is simplified.Thus,

by the use of this invention there results at once 8 very substantiallyreduced cost and improved quality of casting.

In- Fig. 5, I have illustrated graphically the saving achieved by mygate and riser combina- L tion over a typical conventional arrangement.The closely cross hatched area shows in cross section the amount ofextra metal needed to fill the conventional arrangement which is savedby my present invention. r

In Fig. l, as described above, I have used a recess in the outer surfaceof the mold itself to serve as a part of the riser channel. When theapplication, Serial No. 87,086, filed June 16, 1936,

it may be more desirable to construct a .complete unit which is merelyclamped to the end of the mold with its opening ll registering with thecorresponding opening into themold cavity.-

This I have shown in Fig. 4. In this case the construction is similar tothat of Figs. 1 to 3 excepting that the channel member Ha for'the riserextends down as a complete mate for the channel member l5, thus making apouring and riser unit complete in itself even before attachment to themold. Such a unit may be used with plaster molds, with sandmolds, withpermanent molds or in any case where a gate and riser should otherwisebe provided. I

In Figs. 6 and 'l, I have shown another embodiment of the inventionwherein-the connector between the riser and the mold cavity is in theform of a relatively long vertical slot llb; and in this instance thepartition l9b between the gate and riser is pierced at several points byopenings 20, 20', 20". Other parts shown in these figures are similar tothose shown in Figs. 1 and-3 and are similarly numbered.

With many castings the design may be such that better results can beobtained by filling and feeding the mold cavity through a connector orconnectors extending over a considerable distance. In such case it isvery advantageous to use a series of openings as shown in Figs. and 8.This enables the top parts of the casting to be filled with hot metalflowing directly through the upper opening or openings as the level ofthe I metal rises in the mold, rather than by metal which has beencooled off by having first to .fiow through a lower opening. Thus thecasting may be poured at substantially lower tempera-' ture withoutdanger of the metal freezing on in the mold before the mold is entirelyfilled.

It will be obvious that by changing the number and position of theopenings in the dividing partition it is possible to meet very easilythe geting requirements of a great variety of casting designs. regulatedby merely varying the size of the opening or openings in the partition.Funnels of a single design or a few standard designs and sizes can thusbe used on a great range of applications. '75 of dimensions adapted tohold the metal there- The rate of flow of the metal can be In Figs. 9and 10, I have shown two examples of the manner in which the inventionmay be adapted to plural castings. This arrangement has the furtheradvantage that a single pouring funnel 150 or lid may be connecteddirectly to and arranged directly adjacent a plurality of molds arrangedin 'a single unit with a plurality of risers for the several castings,or with a common riser communicating with theseveral molds, all of whichmay be poured in a single operation. By reason-of the common gate orcommon riser and gate, the amount of metal required for casting is thusfurther reduced; and,

' by reason of the proximity of the several risers and central positionof the gate and riser unit between the mold cavities, there is a greatereconomy of heat in gate and riser unit which permits a reduction in thevolume of metal required for each riser, thus eflecting still furthereconomy.

Although I have shown only a fragment of each mold with a single gateand riser unit, it

, will be understood, of course, that for many castings gates and/orrisers will-be required at a plurality of positions distributed aboutthe castings. the standard units may be applied to openings at any orall of these positions and may serve as both gate and riser or as' riseralonei. e.,

metal may be poured into all or less than all of the units provided.Where the unit is used solely as a riser the central partition I9 may beomitted, as its function is not then required,

although there is no objection to using the unit in exactly the sameform as shown.

- It will be obvious to anyone acquainted with I gating practice thatthe relative. proportions of the channels on the sides of the partitioni9 may be varied somewhat according to the requirements of particularcastings, andthat no fixed ratio is necessary to effect the purposes ofthe invention. It -will be advantageous, however, to keep the riserchannel as large in proportion to the gate channel as is consistent withconvenient and satisfactory pouring of the metal.

What I claim is:

v .1. A combined pouring gate and riser unit for casting molds whichcomprises a pair of channeled insulating members of refractory materialadapted to fit together with the sides of their respective channelsengaging one another, one of said members having its channel open at itsupper end to form a pouring funnel, and the other of said channelshaving an opening near its lower end adapted to communicate with thecavity of a casting mold and of dimensions adapted to hold the metalthereof molten until after freezing of the metal in the mold, alongitudinal partition between said members adapted to separate theirrespective channels but having a low opening near its lower end throughwhich molten metal may flow with a skimming action, and a jacket adaptedto hold said members together and augment their mechanical strength.

2. A combined pouring gate and riser unit for casting molds whichcomprises a pair of channeled members of a calcined plaster of Pariscomposition adapted to fit together-with the It is an advantage of myinvention that.

of molten until after freezing of the metal in themold, a longitudinalpartition of asbestos paper between said members adapted to separatetheir respective channels but having a low opening near its lower endthrough which molten metal may flow with a skimming action, and a jacketadapted to hold said members together and augment their mechanicalstrength.

3. A combination pouring gate and riser unit for casting molds whichcomprises a channel part of refractory thermal insulating materialhaving an opening at its upper end adapted to receive molten metal.poured therein and an opening near its lower end through which itcommunicates with a cavity of a casting mold to feed molten metalthereto and of dimensions adapted to hold the metal thereof molten untilafter freezing of the metal in the mold, and a longitudinal partition inthe channel of said part dividing it longitudinally into a pouring gateand riser, said partition having low heat capacity and low heatconductivity'and having a narrow opening near the bottom of said channelthrough "which molten metal must pass in flowing to the mold cavity andthe riser from the pouring gate.

4. In combination with a casting mold, a pouring gate, a riser close tosaid pouring gate, communicating therewith through a low opening adaptedto skim molten metal flowingtherethrough, and communicating with themold cavity by an opening much larger than the skimming opening and ofdimensions adapted to hold the metal thereof molten until after freezingof the metal in the mold, said riser and pouring gate being in closeheat-exchange relation with one another and together insulated fromexternal cooling.

5. A combined pouring gate and riser unit for casting molds whichcomprises a pair of channeled members adapted to fit together with thesides of their respectiv channels engaging one another, one of saidmembers having its channel open at its upper end to form a pouringfunnel, and the other of said channels having an opening near its lowerend adapted to' communicate with the cavity of a casting mold and ofdimen-. siOns adapted to hold th metal thereof molten until afterfreezing of the metal in the mold, and a longitudinal partition betweensaid members adapted to separate their respective channels but having alow opening through which molten metal may flow with a skimming action.

6. In combination with a casting mold, a combined gate and riser unitadjacent to said mold and comprising a channeled member having its upperend open for receiving molten metal and its lower end closed from theatmosphere but communicating with the interior of said mold through anopening of dimensions adapted to hold molten metal therein until afterfreezing of the metal in the mold, and a longitudinal partition at oneside of the channel having at least one'low'opening therein throughwhich metal a may pass in its flow from said channel to the interior ofthe mold,

'7. The combination as defined in claim 6, in which metal receivingcavities extend beyond the said opening on both sides of the partition,whereby heat of the metal around the opening tends to keep open acommunication of liquid metal from side to side through such opening.

8. In combination with a casting mold, a combined riser and gate unithaving a channel therein open at the top and provided with an openingfor communicating with the mold, the shortest diameter of said openingbeing not substantially less than the thickness of the metal part to be.

cast thereby, and a thin perforated longitudinal partition of refractorysheet material dividing said channel longitudinally, wherebyj metalpoured on one side of the partition as into a pouring gate is skimmed byflowing through said perforations before entering the casting mold.

9. In combination with a pluralityof casting molds, a combined gate andriser unit adjacent .to all of said molds and comprising a channeledmember having therein a pouring channel common to said several moldsopen at the top to form a pouring gate and closed at the bottom, buthaving an opening communicating with the interior of each mold,said'channeled member being positioned between and close to said molds,whereby the metal in said channel and openings may remain liquid untilthe metal in the casting has substantially solidified, and being dividedby a tubular partition open at its upper end and having a low openingnear its lower end, and spaced from the outer wall of said channeledmember whereby to providea peripheral riser surrounded by andcommunicating with the several molds MORRIS BEAN.

